Since its inception in 1972 the biennial Gordon Research Conference on Microbial Toxins and Pathogenicity has formed a prime focal point for researchers studying microbial pathogenicity and relataed subjects. Recent advances in understanding the mode of action of known toxins at the molecular level, the identification of new toxins and virulence factors and the application of new genetic, biochemical and immunological techniques to basic questions of pathogenic mechanisms have made this area one of the most exciting in modern biology. The 1984 Conference will focus on the regulation of microbial toxins and virulence factors. General sessions are planned on genetics of bacterial virulence factors, processing and secretion of bacterial virulence factors and protein structure and application. Individual sessions will focus on organisms of current interest and importance including sessions on; Staphylococcal virulence factors, Streptococcal pathogenesis, pertussis toxin, anthrax toxin and enterotoxins. Individual lectures include not only one on genetics of soluble factors (toxins) but adherence factors, antigenic variability and invasiveness. Poster sessions will complement the plenary sessions.